Domtar’s wood chip conveyor runs from the Ohio River
all the way to the Hawesville mill’s gates. The mile-long
conveyor moves 750,000 tons/year of wood chips from
barges to the mill, a volume that represents a pile of
chips as high as the Empire State Building and as wide
as a football field.

Five years after introducing a barge unloading system,
Domtar reports that its Hawesville Mill continues
to embark on projects to increase reliability
and performance in producing pulp and paper.
These continuous improvement (CI) projects are
saving time, reducing costs, increasing efficiency
and lowering our environmental impact.

Conveyor belt reduces traffic, pollution.
In 2014, Domtar worked with Ingram Barge Co.
to develop a barge unloading system that uses a
mile-long conveyor to deliver wood chips from
the banks of the Ohio River to the mill. The system
eliminates the need for truck transportation,
which has drastically reduced traffic
congestion and pollution. In its five years of operation,
the conveyor has eliminated over
270,000 truck trips from local roads and
saved about 550,000 gallons of fuel.

“The Hawesville mill chip conveyor is an
agile and unique solution that’s paying dividends
for us,” says Bill Edwards, VP of manufacturing
for communication papers. “It’s just
one example of a number of continuous improvement
projects at the mill — and across our
entire mill system — that are allowing us to
take another step forward in productivity and
reliability.”

Data analysis increases efficiency. Another
CI project is a plant analysis and visualization
tool called PARCview, a system from
dataPARC, Vancouver, WA. It monitors up-tothe-
minute manufacturing data across Domtar’s
network of 13 pulp and paper mills.

Hawesville is testing a state-of-the-art wood
chip moisture analyzer to provide operators
with real-time data to keep the mill’s chip digesters
running smoothly. “Chip moisture can
vary based on any number of conditions,” says
Hawesville mill manager Grant Forrest. “Differences
in wood density due to moisture can
cause variability in our digester’s yield.”

Historically, the mill tested chip moisture
weekly. Those data weren’t timely, so couldn’t
be used to control digester operations. “Realtime
data is key,” Forrest says. “With the chip
moisture analyzer, we will be able to better
manage our chip blends and liquor flow to optimize
the digester and reduce variation.”

Better design reduces downtime. Woodchip
flow through the digester is another area
ripe for improvement. Over the past three
years, the mill had lost an average of 3,500 airdried
tonnes of production due to uneven chipflow
unevenly through the bin, creating plugs.
So the team contacted the bin manufacturer to
discuss the issue.

“In working with the equipment manufacturer,
we discovered they made a design change
after installing our bin that improved chip bin
flow,” Forrest says. “We incorporated the design
change and reoriented the bin during our fall
2018 outage, and the results have been much
improved.” Domtar’s Kamloops, BC, mill saw
similar improvements after updating its chip
bin so that instead of relying on gravity to move
the chips, mechanical screw feeders at the bottom
of the bin churn the chips to move them
through the bin more reliably. As a result, the
mill was able to increase its daily pulp production
by 8%.